Re: [PATCH 3/5] mm: export zap_page_range_single and list_lru_add/del

["David Hildenbrand (arm)" <david@kernel.org>]

On 2/5/26 12:04, Alice Ryhl wrote:
> On Thu, Feb 05, 2026 at 11:59:47AM +0100, David Hildenbrand (arm) wrote:
>> On 2/5/26 11:51, Alice Ryhl wrote:
>>> These are the functions needed by Binder's shrinker.
>>>
>>> Binder uses zap_page_range_single in the shrinker path to remove an
>>> unused page from the mmap'd region. Note that pages are only removed
>>> from the mmap'd region lazily when shrinker asks for it.
>>>
>>> Binder uses list_lru_add/del to keep track of the shrinker lru list, and
>>> it can't use _obj because the list head is not stored inline in the page
>>> actually being lru freed, so page_to_nid(virt_to_page(item)) on the list
>>> head computes the nid of the wrong page.
>>>
>>> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
>>> ---
>>>    mm/list_lru.c | 2 ++
>>>    mm/memory.c   | 1 +
>>>    2 files changed, 3 insertions(+)
>>>
>>> diff --git a/mm/list_lru.c b/mm/list_lru.c
>>> index ec48b5dadf519a5296ac14cda035c067f9e448f8..bf95d73c9815548a19db6345f856cee9baad22e3 100644
>>> --- a/mm/list_lru.c
>>> +++ b/mm/list_lru.c
>>> @@ -179,6 +179,7 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item, int nid,
>>>    	unlock_list_lru(l, false);
>>>    	return false;
>>>    }
>>> +EXPORT_SYMBOL_GPL(list_lru_add);
>>>    bool list_lru_add_obj(struct list_lru *lru, struct list_head *item)
>>>    {
>>> @@ -216,6 +217,7 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item, int nid,
>>>    	unlock_list_lru(l, false);
>>>    	return false;
>>>    }
>>> +EXPORT_SYMBOL_GPL(list_lru_del);
>>>    bool list_lru_del_obj(struct list_lru *lru, struct list_head *item)
>>>    {
>>> diff --git a/mm/memory.c b/mm/memory.c
>>> index da360a6eb8a48e29293430d0c577fb4b6ec58099..64083ace239a2caf58e1645dd5d91a41d61492c4 100644
>>> --- a/mm/memory.c
>>> +++ b/mm/memory.c
>>> @@ -2168,6 +2168,7 @@ void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
>>>    	zap_page_range_single_batched(&tlb, vma, address, size, details);
>>>    	tlb_finish_mmu(&tlb);
>>>    }
>>> +EXPORT_SYMBOL(zap_page_range_single);
>>
>> Why not EXPORT_SYMBOL_GPL?
> 
> I just tried to match other symbols in the same file.

We were probably a bit too sloppy with some of these in the past. But:

davhil01@e142025:~/git/linux$ grep -c "EXPORT_SYMBOL(" mm/memory.c
12
davhil01@e142025:~/git/linux$ grep -c "EXPORT_SYMBOL_GPL(" mm/memory.c
10

So just go with EXPORT_SYMBOL_GPL unless there is a good reason why not.

-- 
Cheers,

David